Push-button matrix switching device



NO V. 10, 1970 v VAN GELDER ET AL 3539, 958- PUSH-BUT'I'ON MATRIX SWITCHING DEVICE Filed Feb. 26, 1969 s Sheets-Sheet 1 INVENTORP GOZEWIJN VAN GLDER GERRIT J.ELZINGA AGENT Nov. 10, 1970 VAN GELDER EI'AL 3,539,958

PUSH-BUTTON MATRIX SWITCHING DEVICE 3 Sheets-Sheet 2 Filed Feb. 26 1969 INVENTOR. GELDER JN VAN J.ELZING A G NT GOZEWI GERRIT BY Nov. 10,1 970 G. VAN GELDER ETAL 3,539,958

PUSH-BUTTON MATRIX SWITCHING DEVICE Filed Feb. 26, 1969 z Sheets-Sheet 5 INVENTOR) GOZEWIJN VAN GELDER GERRIT .I.ELZINGA BYZ AGRNT United States Patent U.S. Cl. 335206 Claims ABSTRACT OF THE DISCLOSURE A push-button swtching device comprising springloaded coupling members, arranged along coordinates and provided with permanent magnets and contacts in artight envelopes actuated by said magnets said device comprising a plurality of push-buttons for the selective actuaton of the coupling members.

In push-button switching devices the problem arises of constructing a compact form so that, for example, the device can be incorporated in existing apparatus of given dimensions It is furthermore important that the basic constructon of these devices should allow adaptation to diflerent switching codes used in practice without the need for carrying out drastic modifications from the manufacturing point of view. The desired compact construction nvolves furthermore the problem of avoiding magnetic stray fields of adjacent permanent magnets which have to actuate an individual contact.

It is known (from Dutch patent application No. 249,668) in respect of push-button swtching devices to impart to coupling members arranged along coordinates a movement transverse of the direction of movement of all push-buttons. These coupling members displace permanent magnets connected therewith in the direction of length of stationary contacts arranged in artight envelopes, so that these contacts are opened or closed.

This known constructon has the disadvantage that the orthogonal directions of movement of the push-buttons and the coupling members and the horizontal dspostion of the contacts in artight envelopes require a comparatively large structural volume. Moreover, the nature of this known constructon is less suitable for obtaining devices matching different switching codes.

The invention has for its object to provide a construction which obviates said disadvantages.

According to the invention this is achieved by causing the push-buttons and the coupling members to move in the same direction and over substantially equal distances, said direction of movement being parallel to the direction of the parallel longitudinal axes of the contacts in the artight envelopes.

In an advantageous embodiment of the switching device in accordance with the invention at least one coupling member is T-shaped, the transverse arm of which is located in a plane at right angles to the direction of movement of the push-buttons and extends along one of the coordinates, while there is provided preferably one further coupling member having a recess accommodating a tranverse arm of a T-shaped member. A further advantageous embodiment of the invention is characterzed in that the device comprises a holder closed at one end by a detachable bottom plate and at the opposite end by a detachable cover plate positioning the coupling members and having apertures accommodating the push-buttons; in the holder the contacts in the airtight envelopes are mounted so that their longitudinal axes are normal to the bottom plate, with the contacts 3,539,958 Patented Nov. 10, 1970 ice extendng through a guide system fixedly arranged between the bottom plate and the cover plate for the coupling members, each of the contacts in the artight envelope being included in printed wiring on the bottom plate.

In a further advantageous embodiment a permanent magnet cooperating with a contact in an artight envelope is formed by two plate-shaped portions arranged side by side in the direction of movement and polarized in opposite senses transversely of their planes, said portions being preferably arranged in two adjacent, slightly ofset recesses, means being provided to urge the two magnet plates in these spaces against stops formed by their relatively staggered positions.

The invention will now be described with reference to a drawing which shows an embodiment.

FIG. 1 is a schematic plan view of a switching device embodying the invention suitable for use with a socalled 2-out-of-7 code.

FIG. 2 shows a developed view of a switching device embodying the invention suitable for use in telephone apparatus.

FIG. 3 is a schematic plan view like FIG. 1 of a switching device embodying the invention suitable for a so called at the most 3-out-of-5 code.

The switching device shown in FIG. 1 comprises twelve push-buttons designated by the numerals 1, 2, 3, 4, 5, 6, 7, 8 and 9 and the symbols 0 and These'push-buttons are arranged in a matrix (4 rows of 3 buttons or else 3 columns of 4 buttons each) and they are adapted to move at right angles to the plane of the drawing. Each push-button actuates two coupling members of diflerent kind by the cooperation between end faces provided at the push-buttons and the coupling members. One kind of coupling member designated by X X X X, is T-shaped, the transverse arms extending parallel to the plane of the drawing in the X-drection coinciding with the direction of the rows and the central limbs being at right angles to the plane of the drawing. These coupling members are adapted to move at right angles to the plane of the drawing. The other kind of coupling members designated by Y Y Y Y has a complicated shape, which will be described more fully with reference to FIG. 2. These Y-members extend in the Y-direction coincdng with the direction of the columns of said array and they are also adapted to move at right an-gles to the plane of the drawing. When an arbitrary push-button of a given row is depressed, the same T- shaped X-member is invariably actuated. For the pushbuttons, 1, 2 and 3 this is the coupling member X In accordance with the column of the selected push-button the coupling member Y Y or Y., is actuated. The coupling member Y is always actuated by the depression any push-button whichever in an identical manner by the cooperation with all X-members. The places where the coupling members cooperate with each other and the push-buttons cooperate with the members Y Y and Y are shaded in FIG. 1. The cooperation between the pushbuttons and the X-members is not illustrated; this will be apparent from the figure by the overlap of the circum ferential lnes of push-buttons and coupling members.

In order to control seven stationary magnetic contacts in artight envelopes the coupling members are provided with permanent magnets (shown in FIG. 1 in a dotted plan view), which are displaced upon a movement of the coupling members along said contacts designated by the letters A, B, C, D, E, F, G and A.V.C. The push buttons and controlling both the A.V.C. contact (general break-contact) for interrupting the microphone circuit in a telephone set, may be employed for local communications and for ingress. All contacts formed in the shape of the known dry reed contacts, have their longitudinal axes normal to the plane of the drawing. For further explanations a survey follows to indicate which push-buttons actuate given coupling members and contacts; it should be noted that the relevant configuration of coupling members, magnets and contacts provdes said "2-out-of-7 code, which means that each push-button actuates a combination of two contacts of a total of seven contacts characteristic of said push-button (the AVC- contact being left out of consideration) FIG. 2 shows a switchng device embodying the invention, which may be employed advantageously inter alia by its greater speed in telephone sets instead of the conventional selection units comprising the rotatable dial. It will be obvious that especially for this purpose a compact structure is required (the dmensions are prefixed), While magnetic stray fields from the control-magnets have to be at a minimum in order to avoid relative elects. FIG. 2 illustrates all essential elements in their basic form and relationship both for the 2-out-of-7 code and the at the most 3-out-of-5 code to be described hereinafter. For the sake of clarity the push-buttons and the coupling member X, actuated thereby and the coupling members Y and Y as well as the associated conductors, contacts and the separate coupling members Z to be described With the at the most 3-out-of-S code are omitted.

A substantially cylindrcal plastic holder 1 is closed at one end by a detachable bottom plate 3 and at the opposite end by a detachable cover plate 5. Between the bottom plate and the cover plate a guide system 7 of a synthetic resin forms an integral part of the holder 1 and is made in common herewith by injection moulding. The holder 1 comprises plastics njection-moulded T-shaped coupling members X X and X The central limbs of said coupling members are guided in apertures of the system 7. The figure shows only the central limbs 9 and 11 of the coupling members X and X which are adapted to slide in gudes 13 and 15 of the system 7. Plastics coupling members Y and Y (FIG. 2 shows only two Y-members) extend transversely of the direction of the arms of the T-shaped coupling members X X and X and are provided With recesses 17 and 19 in which parts of the arms of the members X etc., are freely movable. For example, a transverse arm of the T-shaped coupling member X extends across the recess 19 of the coupling member Y The coupling members have a sliding limb (21 on the coupling member Y by which they are guided in the system 7, all corresponding guide paths of which are identical.

Near each of the crossings of one coupling member X and one coupling member Y a plastic push-button is arranged, each of which comprses a press portion and a sliding limb guided in the system 7. The finger-controlled press portion of the button is hollow, the cavity being divided by a partition into two compartments. With the push-button 2 the press portion is designated by 23, the sliding limb by 25 and the two compartments by 27 and 29. The compartments of the buttons 2, 3 and 8 nearest the sliding limbs (compartment 27 in push-button 2) serve for positionng and guiding the T-shaped coupling members X X X X which are provided With guide pieces for this purpose. With X and X the guide pieces are designated by 31 and 33. The coupling members Y have similar guide pieces; With the coupling member Y shown completely in FIG. 2 this guide piece is designated by 35. The guide pieces of the Y-members, in contrast to those of the X-rnembers, are guided in slits provided on the innerside of the detachable cover plate 5 (for the sake of clarity the slits are not shown in the figure).

The coupling members X are guided on the lower side by their central limbs in the system 7 and on the lower side by means of the press portion of the buttons in the apertures of the cover 5 (see the figure). The cou pling members Y are guided on the lower side by sliding limbs in the system 7 and on the upper side directly in the aforesaid guide slits (not shown) in the cover. Between the bottom plate 3 and the bottom side of all central limbs and sliding limbs springs urge the relevant members towards the cover 5; for the sake of clarity these springs are not shown.

An end face (37 of the button 2) located on the lower side of the hollow press portion of the buttons and the upper face of an X-member constitute mutually cooperating end faces of the push-buttons and of the T-shaped coupling members X. A second end face (41 of pushbutton 2) located on the lower side of the hollow press portion of the buttons and extensions of each Y-member (39 of member Y;) constitute mutually cooperating end faces between the push-buttons and the recessed coupling members Y.

Bach of the coupling members is provided With at least two communicating, relatively oiset recesses intended for accommodating each two plate-shaped, permanent magnets polarized in opposite senses transversely of their planes (the magnets 43 and 45 for the member X Said recesses are bounded on one side by resilient ridges, for example, 47 and 49 of the member X which hold the two magnets tight on the stops 51 and 53 formed by the offset positions of the two recesses. With the X-members these recesses are arranged in the central limbs and With the members Y and Y they are located in the sliding limbs (for example, recesses 55 and 57 in the sliding limb 59 of the member Y The contact between the magnets and the stops provides the advantage that the place of the maximum magnetic field-lne concentration in the transverse plane going through the line of separation between the magnets is accurately defined not only With an individual couplin g member but also in the mutual array of the coupling members. The point up to which the two magnets have to be displaced to actuate the relevant contact can thus be satisfactorily defined. The use of two magnets polarized in opposite senses has the further advantage that said maximum field-line concentration is located in a comparatively small region around said transverse plane. Beyond this region the field-line concentration is considerably lower so that the distance over which the magnets have to be displaced for actuating the contacts may be small (about 6 mms.). Consequently, a transmission mechanism between the push-buttons and the coupling members may be dispensed With. The stroke of the push-buttons must not exceed 6 mms. in order to maintan a convenient control of the switching device. Owing to the omission of a transmission the required structural volume is, of course, smaller so that also viewed in the direction of movement of the push-buttons the device can have a compact form.

Each pair of magnet plates is screened, in order to avoid stray fields, 011 its side remote from the associated contact by a strip of ferromagnetic material extending over the two magnet parts and arranged in the coupling from the foregoing that each of the said limbs will not be associated with a contact. In order to use only a single mould in the manufacture, the system 7 is provided at the beginning at all places where a contact may be provided in the push-button unit, that is to say in the proximity of the guide member of each lmb, with an aperture for the contact.

The contact 61 (and any further contact) is screened on the side opposite the control-magnets concerned by a sheath 65 of electrically conductive material. Near one end of this sheath is provided with an extension 67, which is electrically connected to one of the postions of the contact tongues 69, located outside the envelope of the con tact. Near the other end the sheath 65 is provided with extensions 71 and 73, anchored in apertures 75 and 77 in the bottom plate 3. One of these extensions is elec trically connected to a printed wiring (not shown) on the other side of the bottom plate 3, to which is also connected a portion 79 of one of the contact tongues located near said end. The sheath 65 is furtherrnore provided with a tag 81, by whch it is held in a slit 83 in the cover plate 5 so that the contact 61 and the assocated screening sheath 65 are accurately fixed in place in the device.

As stated above, the press portion of each push-button is hollow, the cavity being divided by a partition into two compartments (see push-button 3 in FIG. 2). One of these compartments serves for guiding the extensions of the X-member (see push-buttons 2 and 5 in FIG. 2), whereas the other compartment serves for guiding a separate coupling member Z (for example 85), the longitudinal axis of which extends parallel to the direction of movement of the sliding member. On the lower side this sliding member is guided like the other coupling members in the system 7. The coupling member Z, the shape of which diflers frorn that of the coupling members X and Y, is required inter alia for obtaining the so-called at the most 3out-of5 code used in practice. The coupling member 85 has an end face 87, whch cooperates upon depression of the button 3 with an end face 89 of said button. FIG. 3 Shows diagrammatically like FIG. 1 the arrangement for an at the most 3-out-of-5 code. Near the push-buttons 4, 6 and a coupling member Z (herein after designated by Z.,, 2 and Z is provided. The contacts are desgnated by the letters A, B B C C D D K and AVC, thecontacts B B C and C D and D being connected in parallel electrically. The button serves in said at the most 3-ont-of-5 code as the earthconnecting button, whch permits consultation. '1'he button may be ernployed for local communications and ingress. For the sake of clarity a survey is again given of the coupling members and contacts actuated by the various pushbuttons.

Pushbutton Coupling members Contacts A.V.O. A+B2+A.V.C Y 2+A.V.C. Y Bi+C1+A.V.C Y 1 A.V.C. X2, Y1, Ze C1+D1+A.V C

A+D2+A.V.C A+B2+D2A.V C X3, Y1, Y3 B2 D2+A.V C X4, Y1, Yfl A+C +A.V.C. 0.-.. X4, Y1, Yz, Y3 A+Bz-ICz-A.VC. Z+ K (b) The addition of three coupling members Z, for whch purpose all push-buttons are appropriate and the guide paths are provided;

(c) The partially different disposition of the end faces of the Y-members cooperating with the push-buttons.

The items (a) and (b) can be satisfied quite readily, since the system 7 is identical for each code and is only utilized in a different manner. The item (0) can be satisfied by starting from a Y-member having four pairs of eX- tensions, given extensions being removed in accordance with the code to be used.

It will be obvious that the push-button assembly described above can be manufactured at very low costs in mass production, since it consists for the major part of njection-moulded synthetic resin. It is not necessary to adapt the njection-moulding machines to the Y-members for the various codes, since the differences from the basic form are slight and can be elirninated from the basic form by means of existing, simple machines such as sawing machines and grinding machines.

What is claimed is:

1. A switching device comprising:

(a) a frame, (b) a plurality of electrical contacts carried by the frame, (c) a plurality of first coupling members carried by the frame, each movable between actuated and unactuated positions, (d) a plurality of second coupling members, each being movable similarly to the first members and being engagable by at least one first member, (e) a magnet carried by each member, (f) first means resiliently urging said members toward their respective unactuated positions, (g) second means comprsing a plurality of elements carried by the frame and movable similarly to said members, each element disposed to engage at least one of said members, whereby movement of each element engages and moves each corresponding member and its magnet, moving same between unactuated t0 actuated positions with each magnet moved into the vcinity of a contact for actuating same.

2. A device as defined in claim 1 wherein each element engages and moves one first member and one second member, and each moved first member engages and moves one additonal second member, whereby the magnets of the three moved members are moved t0 corresponding contacts.

3. A device as defined in claim 1 wherein said second means comprise pushbuttons.

4. A device as defined in claim 1 wherein each contact is a magnetically operated switch in airtight envelope.

5. A device as defined in claim 1 wherein said frame has a princpal axis, said second means comprise pushbuttons, said first and second members and the pushbuttons, are movable along lines generally parallel to said axis, each contact is a magnetically-operated switch, and the first and second members respectively have longitudinal arm parts extending along perpendicular -X and Y coordinates which are normal to said principal axis.

6. A device as defined in claim 5 wherein there are (a) four first members having fout spaced and parallel arm parts generally in a first plane, and (b) four second members having four spaced and parallel arm parts generally in a second and adjacent overlying plane.

7. A device as defined in claim 5 wherein each first member forms a T-shape, with its transverse part forming said arm along the X-axis.

8. A device as defined in claim 5 further comprising a plate including circuitry thereon, the contact being elec trically connected thereto.

9. A device as defined in claim 5 wherein each magnet comprises two permanent magnets formed as plates disposed adjacently and polarized in opposite senses.

10. A device as defined in claim 5 further comprising ferromagnetic screenng means acjacent parts of each FOREGN PATENTS magnet 935,474 8/1963 Great Britain.

References Cited BERNARD A. GILHEANY, Prima1 *y Examiner UNITED STATES PATENTS 5 3292125 12/1966 Bem, R. N. ENVALL, .R., Assistant Examiner 3,448,419 6/1969 Myatt 335-206 

